From their blog:
Huge Bitcoin sell off due to a compromised account - rollback
The bitcoin will be back to around 17.5$/BTC after we rollback all trades that have happened after the huge Bitcoin sale that happened on June 20th near 3:00am (JST).
Service should be back by June 20th 10:00am (JST, 01:00am GMT) with all the trades reversed and accounts available.
The Canadian exchange cavirtex did not collapse, and AFAIK does not need a rollback.